Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752445AbbEFI0x (ORCPT ); Wed, 6 May 2015 04:26:53 -0400 Received: from mailapp01.imgtec.com ([195.59.15.196]:54727 "EHLO imgpgp01.kl.imgtec.org" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752164AbbEFI0s (ORCPT ); Wed, 6 May 2015 04:26:48 -0400 X-PGP-Universal: processed; by imgpgp01.kl.imgtec.org on Wed, 06 May 2015 09:26:46 +0100 Date: Wed, 6 May 2015 09:25:43 +0100 From: James Hogan To: Andrew Bresticker CC: Ralf Baechle , Kishon Vijay Abraham I , "devicetree@vger.kernel.org" , Linux-MIPS , "linux-kernel@vger.kernel.org" , James Hartley , Damien Horsley , Rob Herring , Pawel Moll , Mark Rutland , "Ian Campbell" , Kumar Gala Subject: Re: [PATCH V2 1/3] phy: Add binding document for Pistachio USB2.0 PHY Message-ID: <20150506082543.GC18183@jhogan-linux.le.imgtec.org> References: <1428444258-25852-1-git-send-email-abrestic@chromium.org> <1428444258-25852-2-git-send-email-abrestic@chromium.org> <20150505220116.GE17687@jhogan-linux.le.imgtec.org> <20150505224352.GA18183@jhogan-linux.le.imgtec.org> <20150505233534.GB18183@jhogan-linux.le.imgtec.org> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="qtZFehHsKgwS5rPz" Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) X-Originating-IP: [192.168.154.110] X-ESG-ENCRYPT-TAG: b93fcccb Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5482 Lines: 130 --qtZFehHsKgwS5rPz Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, May 05, 2015 at 06:06:08PM -0700, Andrew Bresticker wrote: > On Tue, May 5, 2015 at 4:35 PM, James Hogan wrot= e: > > On Tue, May 05, 2015 at 04:09:31PM -0700, Andrew Bresticker wrote: > >> On Tue, May 5, 2015 at 3:43 PM, James Hogan w= rote: > >> > On Tue, May 05, 2015 at 03:16:23PM -0700, Andrew Bresticker wrote: > >> >> Hi James, > >> >> > >> >> On Tue, May 5, 2015 at 3:01 PM, James Hogan wrote: > >> >> > Hi Andrew, > >> >> > > >> >> > On Tue, Apr 07, 2015 at 03:04:16PM -0700, Andrew Bresticker wrote: > >> >> >> Add a binding document for the USB2.0 PHY found on the IMG Pista= chio SoC. > >> >> >> > >> >> >> Signed-off-by: Andrew Bresticker > >> >> >> Cc: Rob Herring > >> >> >> Cc: Pawel Moll > >> >> >> Cc: Mark Rutland > >> >> >> Cc: Ian Campbell > >> >> >> Cc: Kumar Gala > >> >> >> --- > >> >> >> No changes from v1. > >> >> >> --- > >> >> >> .../devicetree/bindings/phy/pistachio-usb-phy.txt | 29 +++++++= +++++++++++++++ > >> >> >> include/dt-bindings/phy/phy-pistachio-usb.h | 16 +++++++= +++++ > >> >> >> 2 files changed, 45 insertions(+) > >> >> >> create mode 100644 Documentation/devicetree/bindings/phy/pistac= hio-usb-phy.txt > >> >> >> create mode 100644 include/dt-bindings/phy/phy-pistachio-usb.h > >> >> >> > >> >> >> diff --git a/Documentation/devicetree/bindings/phy/pistachio-usb= -phy.txt b/Documentation/devicetree/bindings/phy/pistachio-usb-phy.txt > >> >> >> new file mode 100644 > >> >> >> index 0000000..afbc7e2 > >> >> >> --- /dev/null > >> >> >> +++ b/Documentation/devicetree/bindings/phy/pistachio-usb-phy.txt > >> >> >> @@ -0,0 +1,29 @@ > >> >> >> +IMG Pistachio USB PHY > >> >> >> +=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D > >> >> >> + > >> >> >> +Required properties: > >> >> >> +-------------------- > >> >> >> + - compatible: Must be "img,pistachio-usb-phy". > >> >> >> + - #phy-cells: Must be 0. See ./phy-bindings.txt for details. > >> >> >> + - clocks: Must contain an entry for each entry in clock-names. > >> >> >> + See ../clock/clock-bindings.txt for details. > >> >> >> + - clock-names: Must include "usb_phy". > >> >> >> + - img,cr-top: Must constain a phandle to the CR_TOP syscon nod= e. > >> >> >> + - img,refclk: Indicates the reference clock source for the USB= PHY. > >> >> >> + See for a list of vali= d values. > >> >> > > >> >> > Possibly dumb question: why isn't the reference clock source spec= ified > >> >> > in the normal ways like the "usb_phy" clock is? > >> >> > > >> >> > Does the value required here depend on what usb_phy clock gets mu= xed > >> >> > from or something? > >> >> > >> >> Right, the value indicates what clock "usb_phy" is: whether it comes > >> >> from the core clock controller, the XO crystal, or is some external > >> >> clock. It's a mux internal to the PHY. > >> > > >> > Okay. If its a software controllable mux, is there a particular reas= on > >> > the DT doesn't describe it as such, i.e. have all 3 clock inputs, and > >> > the driver somehow work out which to use? > >> > >> Well, I'm not sure how the driver would determine which clock to use > >> without a device-tree property like the one I've got here :). Also, > > > > Does it make sense to just look for the "best" usable source clock based > > on the supported rates listed in fsel_rate_map[] (for some definition of > > "best" such as "fastest" / "slowest" / "first usable"), or are things > > just not that simple? > > > > I'm just wondering how the DT writer would decide, since it seems to > > come down to a policy decision rather than a description of the > > hardware, which should probably be avoided in DT bindings if possible. >=20 > Ah, sorry if that was unclear - this *is* describing a hardware > property. The DT author would pick a value by looking at which clock > is connected to the PHY in the schematic. Okay cool. Sorry for the noise. Thanks James --qtZFehHsKgwS5rPz Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQIcBAEBAgAGBQJVSdAHAAoJEGwLaZPeOHZ6xxwP/jKHty710vHJJYfovVyvvMOB mFHIOLYOwbOh2H532NnbBUBKVmsxwfXRfLCdl3mWb+phoodwzA0A9a0pALj3O4iH Uc/HTTV7HOI3d5SFkioOeHNzue1DDnAWnMsEJFsdebdpjz/RC8TZFMI5GnD3bgi9 OmhHgpOLzr03X0Xi/D3cQtpB0VpZIaXRM12gbKn3yrzM8gZP2Rk8jY2xUQz15B9j W0Q0FUxNRhg3JZlhI+5XilJw7b+Php6X8BHlYF/0yumRFL3oi0h6/FpEROXzeTqN 8lQlX8w37OiHyDl9rV+h+pqXc0X9kGeKMBCSgZsy2RBlXCKpOWXxgAKv1KIizUPz EhlbdAzBQ6F2OEFudN/dQSxvWO99c0Ot1o7Vk/eOJvKO+yWp9qbS1oNYEdLy85+Q lNrMdnNGQy4G219Ort5pOy9OU0OgK/oLYJ9QpKXW9Xq5sK2UKvZZpxhGEZv908Ry xWDWeQM7aNxgWxifxkwhK10S6ZDkjnoUL31yQQIlBb3Ef2c+j9/WMhl+g72ACsGM 9r49fdsdeEtGOb8g4ymIQp3j/pOLDj1gyMGhI0jzn4po0c6dlAP8qTWTnDCGDzoo 18dS0m9eKo/pTcj0qeOD+X0l9RUTTlEB8dSQs2Apq2r0haoWaj58CkMQv19FueU4 qCpcmnlWAWcg3zn3ZuM7 =LHaj -----END PGP SIGNATURE----- --qtZFehHsKgwS5rPz-- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/